Finding the Fourth Proportional to 13,405.72, 18,502.10 and 7,439.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,405.72 : 18,502.10 = 7,439.31 : x
2. Step 2: Convert to fraction form
   13,405.72/18,502.10 = 7,439.31/x
3. Step 3: Cross multiply
   13,405.72x = 18,502.10 × 7,439.31
4. Step 4: Simplify right side
   13,405.72x = 137,642,788.17
5. Step 5: Solve for x
   x = 137,642,788.17/13,405.72
6. Step 6: Final answer
   x = 10,267.47